Spark-plug



0. M. LEICH.

w SPARK PLUG. APPLICATION HLED MAR.19. 1919.

1,848,886, Ptented Aug. 10, 1920.

vmaria-'11).s'lxi'lf'es PATENT OFFICE.

osoAR M. LEIcH, or GENoA, ILLINoIs, AssIGNoR To LEICH ELECTRIC COMPANY, or

I GRNoA, ILLINoIs, A CORPORATION or ILLINoIs.

sPARK-PLUG.

Application filed March 19, 1919. Serial No. 283,566.

To all whom it may Gomera:

Be it known that I, OsoAR M. LEroH, a citizen' of the United States, residing at Genoa, in the county ofDekalb and State of Illinois, have invented a` certain new and useful Improvement -in lSpark-l'lugs, of which the following is afull, clear, concise,

and eXact description, reference being hadA to the accompanying drawings, forming a part of this specification.

My invention relates to spark plugs of the type for' use in connection with internalcombustion engines and is designed more particularly as an .improvement over the spark plu disclosed in the 'patent issued to Albert Radtke, No. 1,290,780, on J anuary^7, 1919. Inthe spark plugdisclosed in the said patent there is shown in addition to the two spark electrodes an auxiliary co- 'Operating electrode which is insulated and isolated from the other` electrodes, but is yet in close proximity thereto, thus to increase the effect o f the spark.

This present application is designed to provide an effective and simple manner of 'mounting the auxiliary coperating elec- Fig. 3 is a sectional view on line 3--3 of:

*igs 4', 5 and 6 are perspective views illusp trating the auxiliary electrode and its cooperating insulating mounts;

Fig. 7 is a-view simllar to that of Flg. 2

i of a modified form of the invention, and

-show the 'customary insulating base 10 Fig. 8 is a detail view illustrating more clearly the construction shown in F ig. 7.

Referring more particularly to Fig. 1,.I

through which the central electrode 11 extends, terminating at the upper extremity in the binding post 12. The insula'ting` base 10 is held within a metal sleeve or Shell 13 through the agency of the nut 14. The metal is mounted in the engine. The metal shell 13 'also carries the second main electrode 16.

As before stated, there is provided an auxiliary electrode 17, which in this instance forms part of the metal ring 18. This auxiliary electrode 17'is pointed to facilitate its sparking Operations and is mounted in close proximity to the electrode 11. ,The .auxiliary electrode 17 is entirely insulated from and isolated from the electrodes 11 and 16 and operates in accordance with' the discussion of such an auxiliary electrode as set out in the said patent' to Albert A. Radtke. It is' of course known that the spark gap between the electrodes ll and-16 should always be a given predetermined amount. The auxiliary electrode 17 should be closer to its 4coperating electrode than' 'the other-main electrode. Difiiculty is thus experienced in so mounting this auxiliary electrode that it at all times maintains the.

proper spark gap relationship with its copartcularly to aline this auxiliary electrodein' such a manner that the spark gap between it and .the`main electrode will always be a Constant preoletermined amount. As well understood, this spark gap is small and for that reason accuracy in the mounting thereof is necessary; To vthis end the auxiliary electrode 17 is formed as part of a ring 18 of suitable metal. Two insulating blocks, respectively, the blocks 19 and 20 are provided. The block 20 has a recess 21 together with an inwardly extending slotted por-V t'ion 22,' the recess and slot together accommodating accuratel the auxiliary electrode and its supporting ring. The auxiliary electrode is thus accurately confined in position with respect to the insulating blocks 19 and 'Z 20. The three parts 18, 19 and 20 are assembled together and then fastened into position interiorly of the shell13, this shell being, as customary, constructed of very heavy metal and consequently not easily deformed so as to destroy the desired alinement and position of parts. After the elements 18, 19 and 20 have been forced into position, theedge of the shell 13 is swung over, as shown at 23, thus to confine these parts interiorly of said shell near the eX- tremity thereof. It will be readily apparent that in mounting the structure in this manner, the spark gap relationship between the parts is aceurately'maintained.

It furthermore makes it impossible for Specificaton of Letters Patent. Patented Aug. 10, 1920.

the user, and at the same time unnecessary, to in any way attempt to regulate the spark gap relationship between the electrodes 11 and 17.

. In Fig. 7, I show a modified form of the invention in which the auxiliary electrode 17a is fiXedly mounted in an insulating carrier 24, which carrier 4is permanently secured in position upon the shell 13a. Even though the user attempted to bend the auxil-` 'iary electrode 17a, yet such attempted bend ing or adjustment will not cause any appreciable change in the spark gap because of the radial position of the said auxiliary electrode 171L relative to the main electnode 11'.

From What has been thus described, the nature of my invention Will' be readily' clear to those skilled in the art. I claim as my invention the following:

1. A spark plug of the character described having main electrodes and an auxiliary electrode, a metal sleeve carrying one of lsaid main electrodes, a. porcelain mounting for the other of said main electrodes, and insulating means carrying said auXilia-I'y electrode fixedly carried by said metal sleeve independently of said porcelain mounting.

2. A spark plug. of the character described having. main electrodes and an auxiliary electrode, a metal sleeve carrying one of said'main electrodes, and 'insulating means carrying said auxiliaryelectrode fixedly carried by said metal sleeve, said insulating means being arranged interiorly of said sleeve and being held in position by an overhanging portion of said sleeve. 3. A spark plug of the character described having 'main electrodes and an auxiliary electrode. a metal sleeve carrying one of said edly carried by said metal sleeve 'and independent of said supporting means.

5. A spark plug of the character described having main electrodes and an auxiliary electrode extending radially toward one of said mam electrodes, a metal sleeve carrying one of sald mam electrodes, and insulatmg meansvcarrying said auxiliary electrode fixedly carried by said metal sleeve, said insulating means having means to prevent said auxiliary electrode from moving inwardly toxvard its coperating main electrode.

6. A sparl; plug of the character described having main electrodes and an auxiliary .electrode extending radially toWard one of said main electrodes, a metal sleeve carrying one of said main electrodes, and insulating means carrying said auxiliary electrode, said insulating means having means to prevent saidauxiliary electrode from moving inwardly'toward its coperating main electrode.

In Witness Whereof, I hereunto Subscribe my name this 4th day of February, A. D.

` OSCAR M. LEICH. 

